I have flown gassers for about 17 years, never had to put a Bosch cap on any of them..Zenoahs of ALL sizes, Quadras, and a few others..My radio is a 1972 ProLine AM converted to a MicroPro 8000 many years ago...The Dean's plugs usually don't come apart, but a piece of vinyl tape or heat shrink will be good insurance..
Bosch caps come from C&H....You can put it on yourself, it just screws onto the end of the spark plug wire and the ground strap is soldered to the Bosch outer shell...